Intel SA-1100 manual Codec Write Completed Flag CWC read-only, noninterruptible, 11-166

Peripheral Control Module

11.12.6.12Telecom Receive FIFO Not Empty Flag (TNE) (read-only, noninterruptible)

The telecom receive FIFO not empty flag (TNE) is a read-only bit that is set whenever the telecom receive FIFO contains one or more entries of valid data and is cleared when it no longer contains any valid data. This bit can be polled when using programmed I/O to remove remaining bytes of data from the receive FIFO because DMA service and CPU interrupt requests are made only when four or more bytes reside within the FIFO (3, 2, or 1 bytes may remain at the end of a frame). This bit does not request an interrupt.

11.12.6.13 Codec Write Completed Flag (CWC) (read-only, noninterruptible)

The codec write completed (CWC) flag is set after the following sequence occurs: a register write command is issued to the codec by writing to MCDR2; the write command is sent to the codec via subframe 0; the data value is latched within the addressed codec register at the beginning of subframe 1 (the 65th bit of the frame); the address and value that was written is returned to the MCP via the next subframe 0; and the returned values are latched in MCDR2. CWC is automatically cleared when MCDR2 is read or written. This bit does not request an interrupt.

11.12.6.14 Codec Read Completed Flag (CRC) (read-only, noninterruptible)

The codec read completed (CRC) flag is set after the following sequence occurs: a register read command is issued to the codec by writing to MCDR2; the read command is sent to the codec via subframe 0; the data value contained within the addressed codec register is loaded into the codec’s serial shift register during subframe 0 (the 41st bit of the frame); the address and value that was read is returned to the MCP via the same subframe 0; and the returned values are latched in MCDR2. CRC is automatically cleared when MCDR2 is read or written. This bit does not request an interrupt.

11.12.6.15 Audio Codec Enabled Flag (ACE) (read-only, noninterruptible)

The audio codec enabled (ACE) flag indicates when the audio codec input and/or output is enabled, which in turn, indicates that the audio sample rate counter is enabled. This flag is set after the following sequence occurs: a register write command is issued to Audio Control Register B (register 8), and either bit 14 or 15 is set (aud_in_ena or aud_out_ena) by writing to MCDR2; the write command is sent to the codec via subframe 0; the data value is latched within codec register 8; and SFRM is asserted to indicate the start of the next frame. ACE is automatically cleared using the same sequence with the exception that bits 14 and 15 are cleared, disabling both the input and output paths of the audio codec. This bit does not request an interrupt.

11.12.6.16 Telecom Codec Enabled Flag (TCE) (read-only, noninterruptible)

The telecom codec enabled (TCE) flag indicates when the telecom codec input and/or output is enabled, which in turn, indicates that the telecom sample rate counter is enabled. This flag is set after the following sequence occurs: a register write command is issued to Telecom Control Register B (register 6), and either bit 14 or 15 is set (tel_in_ena or tel_out_ena) by writing to MCDR2; the write command is sent to the codec via subframe 0; the data value is latched within codec register 6; and SFRM is asserted to indicate the start of the next frame. TCE is automatically cleared using the same sequence with the exception that bits 14 and 15 are cleared, disabling both the input and output paths of the telecom codec. This bit does not request an interrupt.

11-166 SA-1100 Developer’s Manual